The use of alumina based catalyst carriers has previously been described in a number of patents including U.S. Pat. Nos. 5,100,859; 5,055,442; 5,037,794; and 4,874,739. Such carriers have a wide variety of potential applications in the catalytic field and are especially useful where the alumina base is alpha alumina.
A catalyst support needs to possess, in combination, at least a minimum surface area on which the catalytic component may be deposited, high water absorption and crush strength. The problem is that usually an increase in one can mean a reduction in another property. Thus high crush strength may mean low porosity. Often the balance is achieved by trial and error making the catalyst carrier art even more unpredictable than other chemical process art.
A way has now been found to design carriers with more confidence as to the final property balance. The carriers of the invention have an excellent balance of crush strength, abrasion resistance, porosity and catalytic performance that make them ideal for a range of catalytic applications. They are based on alpha alumina and the novel process by which they are made assures high porosity and excellent crush strength.